Complementary Modalities: DECT
Katrina Glazebrook1
1Mayo Clinic, Rochester, MN, United States

Synopsis

Dual-energy CT provides material composition information. Removal of the calcium signal (virtual non-calcium VNCa) from cancellous bone allows visualization of the marrow space. Studies have shown high sensitivity and specificity compared to MR in cases of trauma in the scaphoid, hip, knee, and ankle (fig 1,2). VNCa imaging can demonstrate marrow infiltration in cases of metastases and myeloma (fig 3). DECT allows identification of MSU crystals in cases of suspected gout with high sensitivity and specificity compared to aspiration (fig 4,5). Monoenergetic DECT with iterative metal artifact reduction can improve image quality in cases with significant metal artifact (fig 6).

Bone edema associated with acute traumatic injury of the musculoskeletal system can guide the identification of subtle nondisplaced and minimally displaced fractures. On conventional single energy CT, this bone edema is obscured by cancellous bone. Dual-energy CT (DECT) techniques allow for material decomposition and can remove calcium signal - virtual non-calcium (VNCa) images - to visualize intramedullary bone edema with sensitivities and specificity close to MRI in the spine, hip and extremities. Marrow infiltration with metastases and multiple myeloma can also be identified using the VNCa technique. The material decomposition of DECT can demonstrate monosodium crystal deposition within the joints, tendons and ligaments in patients clinically suspected of having gout. Along with other iterative metal reduction techniques, DECT allows significant improvement in image quality in patients with prominent metal artifact.

Acknowledgements

I wish to thank Drs Baffour, Fletcher and McCollough for their valuable contributions to this work.

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Figures

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Proc. Intl. Soc. Mag. Reson. Med. 29 (2021)